Electron Spin Resonance Spectroscopy Investigations on Radiosterilization Feasibilities of Sulfadiazine, Sulfamethoxydiazine and Sulfaquinoxaline

Abstract

In this study, the spectroscopic features of the radiolytic intermediates created upon gamma irradiation of sulfadiazine (SDZ), sulfamethoxydiazine (SMDZ) and sulfaquinoxaline (SQX) sulfa group drugs/drug raw materials have been investigated by electron spin resonance (ESR) technique and the radiation sterilization feasibility of these samples was examined. Irradiated samples exhibited ESR spectra consisting of a few resonance lines that appeared at about free energy level. The radiation yield of the samples was calculated to be relatively low (G = 0.1), indicating that the samples were radioresistive materials. Although the samples were not good dosimetric materials, the identification of irradiated samples from the unirradiated ones was possible in long-term studies, even several months after the irradiation process. The decay activation energy of the radical species was calculated by using the signal intensity decay data derived from annealing studies. The probable radical species with different spectroscopic properties have been discussed which have been accepted to be responsible for the ESR spectra of gamma-irradiated samples. It is concluded that SDZ, SMDZ and SQX can be sterilized by gamma radiation and ESR spectroscopy is an appropriate technique for the determination of their spectroscopic behaviours.